Field of Invention
The present invention relates to a gap adjustment member disposed between a first member and a second member for adjusting the gap between the first member and the second member.
Background Information
Japanese examined utility model application publication No. Hei 3[1991]-20578 discloses a gap adjustment member that is disposed between the bottom surface of a mounting hole of an impeller and an end surface of a drive shaft, to adjust the relative position between the impeller and the drive shaft, which is inserted in a mounting hole of the impeller.
The gap adjustment member disclosed in Japanese examined utility model application publication No. Hei 3[1991]-20578 includes four protrusions that protrude radially outward on the outer perimeter surface thereof. The diameter of a virtual circle that connects the projecting ends of the four protrusions is smaller than the diameter of an annular groove for attaching the gap adjustment member of the impeller, and larger than the diameter of the mounting hole of the impeller. The generation of an axis misalignment between the center of the drive shaft and the center of the inner hole of the gap adjustment member, which is caused by the gap adjustment member falling into the annular groove, is thereby suppressed.